Electron discharge device system



Oct. 6, 1936.

A. LECJTHOLD 2,056,610

ELECTRON DISCHARGE DEVICE SYSTEM Filed May 22, 1933 2 Sheets-Sheet l l I I A \6 l lllmml IIIII Filed May 22, 1933 2 Sheets-Sheet 2 f8 llllllllllllll Patented Oct. 6, 1936 UNITED STATES PATENT OFFICE ELECTRON DISCHARGE DEVICE SYSTEM Switzerland Application May 22, 1933, Serial No. 672,154 In Germany June 27, 1932 10 Claims.

This invention relates to improvements in systems utilizing electron discharge devices and more particularly to means for controlling and regulating the flow of current through an elec- 5 tron discharge device during normal operation thereof and for interrupting such flow upon currence of abnormal conditions in the circuits associated with the device.

An electron discharge device may be utilized it) in combination with suitable apparatus and circuits to form systems adapted to uses such as rectifying, inverting, frequency converting, direct current voltage converting or current interrupting, in which the flow of current may be controlled and regulated by suitable energization of control electrodes within the device. Such energization is preferably produced by applying, to the control electrodes of the electron discharge device, a constant potential of one polarity and by suddenly substituting, at suitable times, another potential of opposite polarity. Such result may be obtained by using mechanical circuit making and breaking means, but such means present the disadvantages of being subject to wear and of requiring constant supervision. By substituting auxiliary electron discharge devices for such means, the energization of the control electrodes of the main discharge device may be controlled without the use of moving parts. The regulation of the flow of current from the main discharge device may be obtained by controlling the operation of the auxiliary discharge device by any Well known regulating means. Upon occurrence of a disturbance, the auxiliary de- 5 vice may be utilized to apply a negative potential on the control electrodes of the main device and thereby to cause interruption of the flow of current therethrough at an earlier instant than is possible by the use of mechanical means. It is, therefore, among the objects of the present invention to provide an improved electron discharge device system in which the control electrodes of the device are energized through auxiliary discharge devices.

Another object of the present invention is to provide an improved electron discharge device system in which a potential of predetermined polarity may be suddenly impressed on the com trol electrode of the device without using mechanical means.

Another object of the present invention is to provide an improved electron discharge device system in which the control electrodes of the 56 device receive direct current potentials which are periodically reversed without using mechanical means.

Another object of the present invention is to provide an improved electron discharge device system in which, upon occurrence of a disturb- 5 ance, a negative potential is impressed on the control electrodes of the device without using mechanical means.

Objects and advantages other than those above set forth will be apparent from the following 10 description when read in connection with the accompanying drawings, in which:

Fig. 1 diagrammatically illustrates one embodiment of the present invention in which the "control electrodes of an electron discharge de- 15 vice operable as an alternating current rectifier or as a direct current inverter are generally negatively energized and become positively energized, at suitable times, through an auxiliary electron discharge device only during normal operation; and

Fig. 2 diagrammatically illustrates another embodiment of the present invention differing from the embodiment illustrated in Fig. 1 in that the control electrodes of the device are generally positively energized and become negatively energized through an auxiliary electron discharge device, at suitable times, during normal operation and are continuously negatively energized during abnormal operating conditions.

Referring more particularly to the drawings by characters of reference, reference numeral 6 designates an alternating current line of any number of phases and energized at any desired voltage of any frequency, herein illustrated as a three phase line. It is assumed that it is desired to transfer energy between line B and a direct current line I, 8 by means of electron discharge device 9, such transfer being effected from line '6 to line I, 8 or vice versa according to the adjustment of the system hereinafter described. Device 9 is provided with a plurality of anodes such as It each having an associated control electrode such as I2 controlling the operation thereof and is provided with an electron emitting cathode l3 connected with conductor 8. The potential of cathode [3 will be herein taken as datum for potentials and all other potentials will be referred thereto unless othrwise stated. The anodes of device 9 may be directly ener- 5o gized from line 6 but, in general, it will be preferred to connect such anodes with line 6 through a transformer having a primary winding M connected with line 6 and a secondary winding 16 having a plurality of phase portions sevs5 erally connected with anodes l l and forming a neutral point connected with conductor 1.

The control electrodes of device 9 are generally negatively energized by means of a battery ll connected with cathode I3 and connected with the control electrodes through resistances l8 and i9. Control electrode l2 may also receive a positive potential from a battery 2| through an auxiliary discharge device 23 and resistance I9, such potential overcoming the potential of battery ll when device 23 is rendered conductive. Device 23 is provided with an anode 22 connected with battery 2i, with a cathode 24 connected with resistances i8 and i9 and with a control electrode 26. Device 23 is preferably of the so-called vacuum type and is so chosen that, for a particular value of the potential of control electrode 26, the current flowing through device 23 is substantially zero and that, upon giving a slight positive increment to the potential of such control electrode, the current flowing through device 23 reaches a substantially constant or saturation value. If an alternating potential is applied between the cathode and the control electrode of such a device the current flowing through such device will be substantially zero during a portion of the cycle of such potential and will have a substantially constant value during the remainder of such cycle, the transition between the period of zero current and the period of constant current being effected substantially instantaneously.

Cathode 23 of device 23 is connected with the positive terminal of a voltage divider 29 receiving voltage from a battery 28. Control electrode 23 is connected with an adjustable tap of voltage divider 29 through a resistance 3i and through one winding of the movable armature 32 of a phase shifter having a primary winding 33 energized from line 6. The voltages of battery 28 and of armature 32 are so chosen that control electrode 23 becomes alternately negative and positive with respect to the potential of cathode 24 at voltages such as to cause instantaneous transition between the conductive and noncondnctive conditions of device ,23. 'Armature 32 is provided with an extension 34 receiving a torque from a solenoid 36 receiving current from line i, 8 and responsive to the magnitude of the voltage thereof. Such torque may be aided or opposed by means of, spring 31 acting on extension 34 or by a suitable combination of springs V producing a torque which is of constant magnitude over the range of movement of the armature. The negative terminal of voltage divider 29 is connected through a battery '38 with the secondary winding of an insulating transformer 39 having the primary winding thereof energized through a voltage divider 4| from a current transformer 42 in the circuit of winding l 4. The secondary winding of transformer 39 is connected with the control electrode 43 of a second auxiliary discharge device 34 having a cathode 36 connected with the negative terminal of voltage divider 2.9. The anode 41 of device 44 is connected with control electrode 26 through the contacts 38 of a relay 39 provided with a time mechanism delaying the opening operation thereof. Device 44 is preferably of the so-called 7 vapor type and the operating vapor therefor may be of any suitable nature such as would be supplied by a drop of mercury 5|. Battery ,38 and current transformer 42 are so selected that, during the flow of normal currents through device 9, the negative voltage of battery 38 is always r t r tha the a o vt s con a y. v a e of transformer 38 so that control electrode 43 is always negative. Upon flow of excessive current through device 9 however the peak of the voltage of transformer 39 exceeds the voltage of battery 38 so that control electrode 43 becomes intermittently positive.

The coil of relay 39 is energized from a battery 52 through contacts 53 which are bridged by a circuit breaker 54, in conductor 8, when such circuit breaker is in'the closed position thereof. Circuit breaker 54 is maintained in such closed position by a latch 55 which is released by suitable means upon flow of excessive current in the one or in the other direction to conductor 8. Such release is preferably effected with the shortest possible time delay by means of a polarized relay 56 responsive to the flow of current from device 9 to conductor 8 or by another polarized relay 51 responsive to the flow of current from conductor 8 to device 9, such relays being well known to the art and having their armatures polarized by suitable means such as a battery 58. Although only the circuits associated with control electrode l2 have been described and illustrated, it will be understood that a similar circuit is provided for the energization of each of the control electrodes of device 9.

As a result of the above connections, control electrode l2 receives continuous potentials from energizing means comprising a first source ll of one or a negative polarity, such potential being applied by way of resistances i8 and I9. Such energizing means also comprise a second source 2! of opposite or a positive polarity, the potential of which is applied by way of resistance is and device 23. functions having multiple aspects, some of such aspects being: Connecting the second source with the control electrode [2 of the main discharge device 3 connected therewith to overcome the potential of the first source, suddenly impressing a potential from the second source on the control electrode, periodically connecting such second source with the control elec-' trode and thereafter disconnecting such source to restore the action of the first source, and reversing the polarity of the control potential impressed on the control electrode either singly or periodically. means 23 is controlled by the armature 32 of the phase shifter, the function of such armature being to render discharge means 23 conductive and non-conductive in response to an electrical condition of line 6, such condition being the Discharge means '23 performs The operation of discharge cyclic variation of the voltage of line B in the a present embodiment. The operation of armature 32 is controlled, by means of solenoid 36, in response to another electrical condition of line I, 8 which is the magnitude of the voltage of such line in the present embodiment. Device 64 controlling discharge means 23 operates in response to the occurrence of abnormal conditions and more particularly in response to the flow of excessive current through device 9 and current transformer 32. The action of device 44 is to overcome the controlling action of phase shifter armature 32 'on the potential of control electrode 26 of discharge means 23, and thereby maintain discharge means '23 non-conductive.

contacts 53 and thereby interrupts the operation of device 44.

In operation, assuming the system to be connected as shown and line 6 to be energized, the anodes of device 9 are sequentially brought to a momentarily positive potential by means of winding I6. The control electrodes of device 9 are generally maintained negative by means of battery II through resistances I8 and I9. Assuming that anode II has become positive, the associated control electrode I2 is at first negative due to the action of battery I'I. Control electrode 26 of device 23 is then negative with respect to cathode 24 due to the impression thereon of a negative potential from voltage divider 29 and of a decreasing negative potential from armature 32. The potential received from armature 32 then becomes positive and suddenly brings control electrode 26 to a positive potential such that device 23 becomes conductive and permits the flow of a constant current therethrough from battery 2| through resistance I8. The positive potential thus impressed on control electrode I2 overcomes the negative potential of battery IT, and control electrode I2 is suddenly energized at positive potential substantially equal to the voltage of battery 2|. The associated anode N then carries current until the flow of current is released through another anode receiving a higher voltage from winding I6. The voltage impressed between cathode 24 and control electrode 26 of auxiliary discharge device 23 then again becomes negative, device 23 again becomes non-conductive and control electrode I2 of device 9 again becomes negatively energized from battery II. The above process is repeated sequentially for each anode and control electrode of device 9 during each cycle of the voltage of line 6 to permit flow of current through device 9. Such flow of current will cause a transfer of energy from line 6 to line I, 8 or from line I, 8 to line 6 depending upon the portion of the voltage cycle of line 6 during which current flows through the several anodes of device 9.

If the voltage of line I, 6 is higher than the value desired therefor, solenoid 36 rotates armature 32 against the action of spring 31, thereby causing the voltage impressed by armature 32 on control electrode 26 to lag with respect to the voltage of line 6. The times of positive energization of the control electrodes of device 9 are thereby retarded and the average voltage of line I, 6 is thereby decreased, such action continuing until the voltage returns to the desired value. If the voltage of line "I, 8 islower than the value desired therefor, spring 31 rotates armature 32 against the action of solenoid '36, thereby causing the voltage delivered by armature 32 to control electrode 26 to lead with respect to the voltage of line 6 with the result that the average voltage of line I, 8 returns to the value desired therefor.

During the above operation, control electrode 43 is constantly negative with respect to cathode 46 as the peak value of the secondary voltage of transformer 39 is less than the voltage of battery 38. Upon occurrence of a disturbance which may be a short circuit in line I, 8 or a backfire in device 9, a flow of excessive current occurs through device 9 and through current transformer 42. Control electrode 43 is thereby brought to a positive potential with respect to cathode 46 during the positive portion of one or of several cycles of the current flowing through current transformer 42,thereby rendering device 44 conductive. Such device being of the vapor type, a flow of current will occur therethrough from voltage divider 29 through armature 32, resistance 3| and contacts 48, such current continuing independently of the subsequent variations of the potential of control electrode 43. As a result of such flow of current, control electrode 26 is brought to a potential which is substantially the potential of the negative terminal of voltage divider 29, and device 23 is continually maintained non-conductive. The control electrodes of device 9 then constantly remain negatively energized from battery I1 and the flow of current through device 9 ceases if the disturbance was a short circuit in line I, 8, or even if the disturbance was a backfire in device 9, provided that no other sources of current are connected to line I, 8. In general, however, there will be other sources supplying current to line I, 8 and, upon occurrence of a backfire in device 9, such sources will send a current therethrough from conductor 8 and cathode I3 to the backfiring anode, winding I6, and conductor I.

At the same instant that device 44 is made conductive, however, latch 55 is always released by either relay 56 or relay 5! so that any current flowing through device 9 due to the presence .of sources across line I, 8 is interrupted by circuit breaker 54. Circuit breaker 54 opens contacts 53, thereby deenergizing the coil of relay 49 and, after a predetermined time delay, contacts 48 are opened, flow of current ceases through device 44, and such device again becomes nonconductive. Device 9 then is again in condition to operate normally.

In the embodiment illustrated in Fig. 2, the control electrodes of device 9 are directly connected with battery 2| through resistances I8 and I9 and are intermittently connected with 1 battery I! through device 23. Control electrode 26 accordingly receives, from armature .32 and voltage divider .29, a voltage which is negative at the times the voltage applied thereon in the embodiment illustrated in Fig. 1 was positive, and vice versa. Solenoid 36 operates in response to the fiow of current through device 9 and conductor I as a result of connection of such solenoid with a shunt 59 in conductor I.

Anode 41 of device 44 is herein connected with i the positive terminal of voltage divider 29 over contacts 48, and cathode 46 thereof is connected with control electrode 26.

In the present embodiment, therefore, the first source of control potentials is battery 2| which is of the one or a positive polarity, and the second source is then battery I! which is of the opposite or a negative polarity. The function of the several elements employed in the system remain the same as in the embodiment in Fig. l with the exceptions that solenoid 36 controls the operation of armature 32 in response to the magnitude of the current through device 9 and conductor I, and that device 44 controls the discharge means 23 to maintain such means conductive upon the occurrence of abnormal conditions such as flow of excessive current through device 9.

In operation, each control electrode I2 of device -9 is generally negatively energized by means of battery I! through device 23, the control electrode 26 of which receives a positive potential with respect to cathode 24 from armature 32 and voltage divider 29. When anode has become positive with respect to cathode d3,

the voltage impressed on control electrode 26 by armature 32 becomes negative. and causes device 23. to become suddenly non-conductive. Control electrode I2 then receives a positive potential from battery 25, thereby releasing the flow of current through anode H. Such processes of. operation are repeated sequentially for each anode of device 9 during each cycle of the voltagelof line 6. In the present embodiment, it is assumed to be desired to maintain the flow of current through device 9 at a constant value. If such current is at a value greater than the value desired therefor, solenoid 36 rotates armature 32 against the action of spring 37, thereby causing the voltage impressed on control electrode 25 by armature 32 to lag behind the voltage of line 6 and causing the average current flowing through the several anodes ofdevice 9 to decrease until the flow of current through shunt 59 is reduced to the value desired therefor. If the current through device ii is smaller than the value desired, spring 3? rotates armature 32 against the action of solenoid 36, thereby causing the voltage of armature 32 to lead with respect to the voltage of line 6 and causing the average flow of current through device 9 to in' crease until such current again reaches the desired value.

Upon occurrence of a disturbance in the system resulting in the flow of excessive current through current transformer 22, device l l'becomes conductive as in the embodiment illustrated in Fig. 1. The current through such device then flows from voltage divider 29 through contacts 48 to control electrode 26 which then is continuously maintained at substantially the potential of the positive terminal of Voltage divider 29. Discharge device 23 is thereby continuously maintained conductive and continuously impresses the negative voltage of battery I! on control electrode l2. As a result of such action all current fiow is interrupted in device 9 with the exception of any current supplied thereto by sources connected with line i, 8 which current is then interrupted upon opening of circuit breaker 56. Such opening results in opening of contacts 53 and thereby causing device id tocease to carry current and to be returned to the non-conductive condition. Device 9 is then again in condition for normal operation. 7

Although but two embodiments of the present invention have been illustrated and described, it Will be apparent to'those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In a system for controlling the flow of electric-current, an electric current line, an electron discharge device connected with said line, said device having an anode and a cathode and having a control electrode associated with the anode, a second electric current line connected with said device, a source of potential of one polarity connected between the control electrode and the cathode, a second source of potential'of another polarity connected with the cathode, electron discharge means operable to connect the second said source with the control electrode, means responsive-to an electrical condition of one of said lines for controlling the operation of said electron discharge means, and

means responsive to another electrical condition of one of said lines for controlling the second said means. I

said device having an anode and a cathode and having a control electrode associated with the anode, an alternating current line connected with said device, a source of potential of one polarity connected between the control electrode and the cathode, a second source of potential of another polarity connected with the cathode, electron discharge means operable to connect the second said source with the control electrode, means responsive to the instantaneous value of the voltage of said alternating current line for controlling the operation of said electron discharge means, and responsive to the magnitude of the voltage of the first said line for controlling the second said means.

3. In a system for controlling the fiow of electric current, an electric current line, an electron discharge device connected with said line, said device having an anode and a cathode and hava control electrode associated with the anode, an alternating current line connected with said device, a source of potential of one polarity connected between the control electrode and the cathode, a second source of potential of another polarity connected with the cathode, electron discharge means operable to connect the second said source with the control electrode, means responsive to the instantaneous value of the voltage of said alternating current line for controlling the operation of said electron discharge means, and means responsive to the magnitude of the current flowing through said device for controlling the second said means.

4. In a system for controlling the flow of electric current, an electric current line, an electron discharge device connected with said line and having an anode and'a cathode and having a control electrode associated with the anode, a second electric current line connected with said device, a source of potential of one polarity connected between the control electrode and the cathode, a second source of potential of another polarity connected with the cathode, electron discharge means operable to connect the second said source with the control electrode, means responsive to an electrical condition of one of said lines for controlling the operation of, said discharge means, and electron discharge means responsive to abnormal conditions in one of said lines for controlling the first said means.

5. In a system for controlling the flower electric current, an electric current line, anelectron discharge device connected with said line and having an anode and a cathode and having a control electrode associated with'the anode, a second'electric current line connected with said device, a source of potential of one polarity connected between the control electrode and the cathode, a second source of potential of another polarity connected with the cathode, electron discharge means operable to connect the second said source with the control electrode, means responsive to an electrical condition of one of said lines for controlling the operation of said electron discharge means, an electron discharge means responsive to the flow of excessive current through said device for controlling the first said means.-

6. In a system for controlling the flow of electric current, an electric current line, an electron discharge device connected with said line and having an anode and a cathode and having a control electrode associated with the anode, a second electric current line connected with said device, a source of potential of one polarity connected between the control electrode and the cathode, a second source of potential of another polarity connected with the cathode, electron discharge means operable to connect the second said source with the control electrode, means responsive to an electrical condition of one of said lines for controlling the operation of said discharge means, and electron discharge means responsive to the flow of excessive current through said device to overcome the action of the second said means.

7. In a system for controlling the flow of electric current, an electric current line, an electron discharge device connected with said line and having an anode and a cathode; and having a control electrode associated with said anode, a second electric current line connected with said device, a source of potential of one polarity connected between the control electrode and the cathode, a second source of potential of another polarity connected with the cathode, electron discharge means operable to connect the second said source with the control electrode, means responsive to an electrical condition of one of said lines for controlling the operation of said discharge means, and electron discharge means responsive to the flow of excessive current through said device to maintain the first said discharge means continuously conductive.

8. In a system for controlling the flow of electric current, an electric current line, an electron discharge device connected with said line and having an anode and a cathode and having a control electrode associated with the anode, a second electric current line connected with said device, a source of potential of one polarity connected between the control electrode and the cathode, a second source of potential of another polarity connected with the cathode, electron discharge means operable to connect the second said source with the control electrode, means responsive to an electrical condition of one of said lines controlling the operation of said discharge means, and electron discharge means responsive to the flow of excessive current through said device to maintain said discharge means continuously non-conductive.

9. In a system for controlling the flow of electric current, an electric current line, an electron discharge device connected with said line and having an anode and a cathode and having a control electrode associated with the anode, a second electric current line connected with said device, a source of potential of one polarity connected between the control electrode and the cathode, a second source of potential of another polarity connected with the cathode, electron discharge means operable to connect the second said source with the control electrode, means responsive to an electrical condition of one of said lines for controlling the operation of said discharge means, electron discharge means responsive to the flow of excessive current through said device to overcome the action of the second said means, circuit interrupting means operable upon flow of excessive current occurring through said device, and means for interrupting the operation of the third said means upon operation of said circuit interrupting means.

10. In a system of the character described, the combination with an electron discharge device comprising an anode with an associated control electrode and a cathode, and a source of current for exciting said electrode to thereby control the moments of initiation of flow of current through said device by way of said anode and cathode, of means comprising an electron discharge device operable to connect therethrough said source with said electrode, means operable, during normal operation of the system, to control the second said device in such sense as to cause the continual connection therethrough of said source with said electrode, and means operable, responsive to an abnormal condition of the system, to control the second said device in such sense as to cause the continuous connection 15 therethrough of said source with said electrode.

ARMIN LEfrrHoLn. 

